Hi BaboonBoy22. I think that as long as both machines can support the external HDD (i.e. the old machine isn't so old that it doesn't have any suitable ports), then what you are proposing should be entirely practical. I'm guessing that by "data" you mean things like word processor files, pictures, old emails etc. Presumably you are aware that program files can't be transferred. I always back up important data files to CD or DVD so they can be restored in case of hard drive corruption or failure, these are then also easy to transfer to a new machine.